This core will provide support for the breeding and tracking of all of the special mutant(knockout) or transgenic mice needed to conduct the experiments proposed in projects 1-3. Our premise is that, to ensure most efficient use of mice in the 3 projects (and to ensure that the interacting projects use mice which have an identical history of breeding and care), mouse care and breeding is best performed by a single facility, which will maintain colonies of each strain and coordinate their use. By providing the mice from a core within the Asthma center, each of the scientific projects requiring mice can concentrate on achieving their basic scientific goals. The Core will be located in The Simon C. Fireman Research Center Animal Facility. This facility, which is located on the floor below that of Drs. Kinet and GalIi, is fully accredited by AAAAAC and the USDA and is staffed by qualified animal care personnel and a licensed veterinarian. In addition to directing the breeding of each colony and tracking mouse genotypes where appropriate, Core personnel will be responsible for carrying out certain pre-experimental treatment protocols. Once breeding is underway at full scale, core personnel will also be responsible for coordinating the use of mice and distributing mice of appropriate age and genotype to the various participating investigators. Furthermore, the personnel will be responsible for keeping appropriate records on the breeding, health, and genotypes of all mice and making sure that these records are available to all investigators. In this way, mice of the appropriate genotype and age, and of uniformly high quality, will be available to all investigators.